Valve grinding machine



DEC. 29, 1970 H BALSlGER 3,550,323

VALVE GRINDING MACHINE Filed Dec. 5, 1967 2 Sheets-Sheet 1 INVENTOR HAROLD E. BQLSIGER ()RNIiYS O lm,

Dec. 29, 1970 BALS|GER 3,550,323

VALVE GRINDING MACHINE Filed Dec. 5, 1967 2 Sheets-Sheet 2 INVENTOR.

HAROLD E. BALSIGER United States Patent M 3,550,323 VALVE GRINDING MACHINE Harold E. Balsiger, Waynesboro, Pa., assignor, by mesne assignments, to Litton Industries, Inc., a corporation of Delaware Filed Dec. 5, 1967, Ser. No. 688,189 Int. Cl. 1824b /02 US. Cl. 51-105 11 Claims ABSTRACT OF THE DISCLOSURE The apparatus of this application consists of a machine bed, a grinding wheel support slidably mounted on said bed for movement toward and from a grinding position, a grinding wheel rotatably mounted on the wheel support, work supporting means having means for rotatably supporting workpieces in peripherally spaced relation to the grinding wheel, the work supporting means having axes intersecting one another and the grinding wheel axis at substantially the same point, whereby to maintain a sub stantially constant angular relation between the surface of the grinding wheel and the surface of the work to be ground.

This invention relates to a valve grinding apparatus for grinding valve seats and other portions of the valve head, and more particularly, to apparatus for grinding more than one valve at the same time.

In grinding the seats of automotive poppet valves, one at a time, the relation between the face of the grinding wheel and the surface of the work being ground depends on supporting the valves for rotation about an axis which always intersects the axis of the grinding wheel. As the grinding wheel becomes smaller due to wear, the grinding wheel must be advanced in order to engage the workpiece. The position of its axis also changes. However, since this advance takes place in the plane which includes the work drive axis, the axes continue to intersect although the point of intersection changes.

In grinding valve seats of automotive valves, two at a time, with the valves supported above and below the horizontal plane passing through the wheel axis, the relation between the face of the grinding wheel and the faces of the valve seats changes as the grinding wheel becomes smaller due to wear and dressing.

In grinding valve seats, two at a time, as described above, the axis of the grinding wheel advances in a plane which does not include the axis of either of the valves. Thus, there is a constant change in the point of intersection of the valve axes with the axis of the grinding wheel. One way to maintain this axial relation constant between the valve axes and the grinding wheel axis, would require that there be a constant change in the angular relation between the valve supporting members as well as between these members and the grinding wheel axis. Such a change would require a rather complex adjusting means. However, the variation in relation between the valve seats and the grinding wheel face is relatively small and this relation may be held within acceptable limits by arranging the work supporting members so that their axes and the axis of the grinding wheel have a common point of intersection when the grinding wheel axis has advanced to the half-way point between maximum and minimum grinding wheel diameters.

Where a greater degree of accuracy is required, the intersecting relation between the grinding wheel axis and the headstock axes can be maintained by swivelling the grinding wheel so that its axis always passes through the point of intersection of the headstock axes as shown in my copending US. application Ser. No. 563,878, filed July 8, 1966, now Pat. No. 3,481,085, issued Dec, 2, 1968.

3,550,323 Patented Dec. 29, 1970 It is, therefore, the object of the present invention to provide a machine for grinding head portions of two valves simultaneously wherein the need for an adjustment other than the advancement and retraction of the grinding wheel axis is eliminated by supporting the valves for rotation about axes which intersect each other as well as the axis of the grinding wheel.

With the above and other objects in view that will hereinafter appear, the nature of the invention will be more clearly understood by reference to the following detailed description, the appended claims and the several views illustrated in the accompanying drawings:

In the drawings:

FIG. 1 is a front elevational view of the valve grinding apparatus and shows the general relationship of the work rotating members thereof with respect to the grinding wheel.

FIG. 2 is a plan view of the valve grinding apparatus of FIG. 1.

FIG. 3 is a schematic perspective view showing the specific relationship of the axis of the grinding wheel with respect to the axes of valves when the grinding wheel is of a mean diameter.

FIG. 4 is an enlarged fragmentary horizontal sectional view taken generally along the line 4-4 of FIG. 1 and shows the specific details of one of the work rotating members.

Referring now to the drawings in detail, it will be seen that the valve grinding apparatus or machine is generally referred to by the numeral 10. The machine 10 has many features which are conventional to grinding machines and therefore, only the features thereof which are particularly modified in accordance with this invention will be described in detail.

The machine 10 includes a bed 11 on which there is conventionally mounted a grinding wheel support 12 for sliding movement in a predetermined straight line direction. The grinding wheel support 12 includes a shaft 13 which has mounted on one thereof a grinding wheel 14. The shaft 13 is driven by means of a motor 15 which is carried by the grinding wheel support 12.

In accordance with this invention, the grinding wheel 14 is disposed in a fixed vertical plane and is advanced and retracted while remaining in that plane. This is accomplished by advancing and retracting the grinding wheel support 12 by means of conventional feed mechanism which is identified by the numeral 16 and will not be described in more detail hereinafter. It is also to be understood that there will be associated with the grinding Wheel 14 conventional dressing mechanism (not shown) for periodically dressing the grinding wheel 14 and maintaining the contour of the face thereof.

The bed 11 also carries a work support 17 which, when adjusted, is preferably retained in the fixed adjusted position. The work support 17 carries a pair of vertically spaced work rotating members or head stock members 18 and 20. The headstock members 18 and 20 are substantially identical and are mounted on the work support 17 in position to hold workpieces W in position for grinding one above and one below the horizontal plane passing through the axis of the grinding wheel 14. The headstock members 18 and 20 are driven by motors 21 and 22, respectively.

Reference is now made to FIG. 4 wherein there is illustrated the specific details of the headstock member 18. The headstock member 18 includes a shaft 24 which is suitably supported in bearings 25 and 26 for rotation, the bearings 25 and 26 being, in turn, supported by a housing 27. At the forward end of the shaft 24 there is a conventional chuck assembly 28 for gripping a workpiece W and holding the same in a predetermined position for grinding by the grinding wheel 14. At this time it is pointed out that the headstock member 18 has associated therewith conventional mechanism 30, which will not be described in detail, for effecting the automatic opening and closing of the chuck 28 as well as the automatic positioning of the workpiece W within the chuck 28 and the automatic ejection of the workpiece after the grinding operation has discontinued and the chuck 28 is moved to an open condition.

At this time it is pointed out that normally the shaft 24 will be rotated by means of a drive belt 31 which is engaged with a drive pulley 32 carried by the shaft 24 remote from the chuck 28.

At this time it is pointed out that the machine may be of the automatic operating type and may be provided with a suitable dual loader, which is generally identified by the numeral 33 and which is best shown in FIGS. 1 and 2. The loader 33 is not a part of this invention and therefore, will not be described in detail.

At this time it is pointed out that although the machine 10 is particularly designed for grinding poppet valves of the type generally used in internal combustion engines, the machine is not so limited in its use. On the other hand, the specific advantages of the machine 10 will be described with respect to a workpiece which is in the form of a poppet valve.

The respective surfaces of a poppet valve must be ground at a particular angle to the axis of the valve. When a single valve is being ground, it is supported and rotated with the axis thereof lying in a common plane with the axis of the grinding wheel, and the grinding wheel being mounted wherein when it is shifted relative to the valve, its axis remains in that common plane. As a result, it is merely necessary to set the angle between the axis of the valve being ground and the axis of the grinding wheel to the desired angle. This angle will remain constant irrespective of the diameter of the grinding wheel.

When it is desired to grind two valves simultaneously, it is necessary to dispose the two valves in equally spaced relation on opposite sides (above and below) the plane in which the axis of the grinding wheel shifts as the grinding wheel is advanced or retracted. Inasmuch as the points of engagement between the valves and the grinding wheel do not lie in the plane of movement of the grinding wheel axis, the angular relationship between the contact surfaces of the grinding wheel and the valves is not the same as that as when the axis of the valve lies in the plane of the grinding wheel axis. Therefore, it is necessary that there be a further modification in the angular relationship between the axes of the workpieces and the axis of the grinding wheel.

With particular reference to the schematic showing of FIG. 3, it will be seen that the axis of each of the workpieces W is disposed at the same vertical angle A to the plane of the axis of the grinding wheel 14. For identification purposes, the axis of the grinding wheel 14 is identified by the numeral 40 with the axis of the workpiece carried by the headstock member 18 being identified by the numeral 41 and the axis of the workpiece W carried by the headstock member being identified by the numeral 42. In addition, the plane of the path of movement of the grinding wheel axis 40 is identified by the numeral 43 In addition to the vertical angle A between the axes 41 and 42 with respect to the plane 43, there is a horizontal angle B between each of the axes 41 and 42 and the grinding wheel axis 40. A proper combination of the angles A and B will provide for the grinding of the desired surface of the workpiece when the grinding wheel 14 is of a predetermined diameter. As will be noted from FIG. 3, when the grinding wheel 14 is of a predetermined diameter and the angles A and B are properly set, the axes 41 and 42 will intersect each other in the plane 43 and along the axis 40.

It will be readily appreciated that the grinding wheel 14 will not remain at a constant diameter due to wear and repeated dressing in order to maintain the necessary contour of the grinding face thereof. Therefore, the specific angular relationship of the various axes, as i lustrat d in FIG. 3, will not remain constant. It will be readily apparent that as the grinding wheel 14 wears, the grinding wheel axis 40 will shift in the plane 43 to a new position parallel to its original position and closer to a line 44 which represents the vertical projection of the axes 41 and 42 in the plane 43. Thus, while the angles A and B will remain constant, the grinding wheel axis 40 will no longer intersect the workpiece axes 41 and 42. It has been found, however, that within the the elfective diameter limits of a grinding wheel, this change will not result in a change of the relationship of the contacting surfaces of the grinding wheel 14 and the workpieces W which is outside of the tolerances for the particular workpiece.

From the foregoing, it will be apparent that the specific angular relationship illustrated in FIG. 3 must be set for the mean diameter of the grinding wheel 14. When the grinding operation commences with a new grinding wheel, the relationship between the contacting surfaces of the grinding wheel 14 and the workpieces W will be on one side of the set angle to be ground on the workpieces and as the grinding wheel reduces in diameter, this variation will diminish until it reaches zero at the mean diameter of the grinding wheel 14. Then the variation will increase as the diameter of the grinding wheel 14 continues to reduce with the variation being on the other side of the designed relationship.

It will also be readily apparent from the foregoing that if it is desired to maintain the relationship of the respective axes 40, 41 and 42 shown in FIG. 3 with the axes 41 and 42 intersecting the axis 40 at the point of intersection with one another, it will be necessary to constantly change the angle B as the diameter of the grinding wheel 14 reduces. A typical manner of mounting the grinding wheel support 12 for swivelling is disclosed in my above-mentioned copending US. application Ser. No. 563,878, now Pat. No. 3,481,085, issued Dec. 2, 1968. In accordance with my prior patent, the grinding wheel support 12 is mounted for guided sliding movement on an intermediate base 12' which is pivotally connected to the bed 11 by means of a pivot P. The base 12' is angularly adjusted relative to the bed 11 about the pivot P and retained in an angularly adjusted position by means of an actuating assembly which is constructed in accordance with my prior Pat. No. 3,481,085. When the grinding wheel support 12 is mounted in this manner, the wheel support may be adjusted angularly at intervals to compensate for the grinding wheel wear. The effect of this adjustment, in conjunction with the particular angular relationship of the axes of the workpieces relative to one another and to the plane of movement of the grinding wheel axis, is to maintain a substantially fixed relationship between the peripheral surface of the grinding wheel and the surfaces of the workpieces being ground.

Since the purpose of this invention is to provide for a most favorable relation between the grinding wheel 14 and the surfaces of the workpieces W being ground as the diameter of the grinding wheel changes due to wear and dressing, and since the sequence of operation of the machine is a conventional one except for the differences described above, further description of the structure and operation of the grinding machine 10 is not believed to be necessary.

Although only a preferred embodiment of the invention has been specifically illustrated and described herein, it is to be understood that minor variations may be made in the valve grinding apparatus without departing from the spirit of the invention.

I claim:

1. In a machine for grinding workpieces which must be held in predetermined angular relation with a grinding wheel,

(a) a grinding wheel support,

(b) a grinding wheel having a periphery mounted on said wheel support for rotation about an axis,

(c) a work support having,

(d) dual work holding and rotating members having axes of rotation spaced about the periphery of the grinding wheel,

(e) means for moving said grinding wheel normal to its axis of rotation towards and away from said work support along a path between said axes of rotation of said work holding and rotating members for simultaneously engaging and grinding workpieces carried by said dual work holding and rotating members, and

(f) said work holding and rotating members being mounted so that their axes of rotation intersect the axis of rotation of said grinding wheel.

2. The machine of claim 1 in which (a) said work holding and rotating members are mounted in angular relation to one another and to the grinding wheel such that their axes of rotation intersect one another and the axis of rotation of said grinding wheel at the same point.

3. The machine of claim 1 in which (a) a common point of intersection of the axes of ro tation of said work holding and rotating members and the axis of rotation of the grinding wheel is effected when the grinding wheel has been worn to mean diameter.

4. The machine of claim 1 in which (a) the relation between the work holding and rotating member axes of rotation and grinding wheel axis of rotation is such that all of said axes intersect at the same common point when said grinding wheel has worn to mean diameter and is in a work grinding position.

5. The machine of claim 1 in which (a) said machine includes a bed, and

(b) cooperating means on said bed and said grinding wheel support for mounting said grinding wheel support for movement of said grinding wheel axis in a fixed plane and for movement between adjacent angularly spaced positions.

6. The machine of claim 1 in which (a) said machine includes a bed,

(b) cooperating means on said bed and said grinding wheel support for mounting said grinding wheel support for movement of said grinding wheel axis in a fixed plane and for movement between adjacent angularly spaced positions, and

(0) means mounting said work holding and rotating members in fixed positions relative to said bed.

7. The machine of claim 1 in which (a) said machine includes a bed,

(b) cooperating means on said bed and said grinding wheel support for mounting said grinding wheel support for movement of said grinding wheel axis in a fixed plane and for movement between adjacent angularly spaced positions, and

(c) said work holding and rotating member being disposed on opposite sides of said fixed plane.

8. The machine of claim 1 wherein (a) said work holding and rotating members axes of rotation are disposed in angular relation to said grinding wheel axis of rotation both in plan and elevation.

9. The machine of claim 1 in which (a) said work holding and rotating members are disposed at one side only of said grinding wheel.

10. The machine of claim 1 in which (a) said work holding and rotating members are disposed at one side only of said grinding wheel and face in the same general direction.

11. The machine of claim 1 in which the spacing between the axes of rotation of said work holding and rotating members is a maximum of 90.

References Cited UNITED STATES PATENTS 1,991,724 2/1935 Binns et a1. 51105X 2,060,396 11/1936 Klein 5 l-95 2,092,117 9/1937 Hall 51105 2,113,387 4/1938 Silven 5l-l05 2,778,163 1/1957 Flygare 5l-105X 

